Clinical, histologic, and radiographic outcomes of distal femoral resurfacing with hypothermically stored osteoarticular allografts

BACKGROUND: Fresh osteoarticular allograft transplantation has a long history of clinical success. These grafts have typically been implanted less than 1 week from donor asystole. HYPOTHESIS: Osteoarticular allografts stored 4 to 6 weeks represent a viable alternative to treat full-thickness cartilage and osteochondral defects of the distal femur as measured by clinical, histologic, and magnetic resonance imaging (MRI) criteria. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Osteoarticular allografts were implanted after a mean graft storage time (at 4 degrees C) of 36 days (range, 28-43). Sixty-seven patients received massive hypothermically stored osteoarticular allografts. Ten knees in 8 of these patients underwent second-look arthroscopic evaluation and biopsy at a mean of 40 months (range, 23-60) after implantation. Clinical assessment was performed using multiple outcome measures and sequential MRI evaluations. Biopsy specimens were obtained from the graft as well as from native articular cartilage at the time of second-look arthroscopy for histologic analysis. RESULTS: The mean International Knee Documentation Committee scores were as follows: preoperative, 27 (range, 9-55); postoperative, 79 (range, 56-99); P = .002. The mean Lysholm scores were as follows: preoperative, 37 (range, 12-47); postoperative, 78 (range, 55-90); P = .002. The mean Short Form-36 physical scores were as follows: preoperative, 38 (range, 24-55); postoperative, 51 (range, 39-61); P = .002. The mean Tegner scores were as follows: preoperative, 4.3 (range, 1-9); postoperative, 5.3 (range, 4-7); P = .16. The mean International Cartilage Repair Society score at follow-up was 10 (nearly normal) (range, 7-11). The mean modified Outerbridge scores were as follows: preoperative, 4.3 (range, 3-5); postoperative, 0.6 (range, 0-1); P = .002. The mean graft and native cartilage cellular density and viability were not statistically different. CONCLUSIONS: Fresh-stored osteoarticular grafts for full-thickness articular surface defects of the distal femur appear to offer a viable biological method to restore knee function. Our study suggests that osteoarticular grafts stored in cell culture medium at 4 degrees C for 4 to 6 weeks provide successful short-term clinical outcomes.     

Osteochondral allograft transplantation

Experience with fresh osteochondral allografting for cartilage defects in the knee now extends two decades. Clinical outcomes and basic scientific investigations have supported the theoretic basis for this procedure. At the University of California, San Diego, our experience has encouraged us to continue to offer this procedure as a primary treatment for both large and small articular cartilage defects in the young knee. The success rate of fresh osteochondral allografting, particularly in isolated femoral condylar defects, compares favorably with other presently available cartilage repair and resurfacing techniques. In our second hundred cases, which we are currently evaluating, failure of monopolar allografts has been exceedingly rare in short-term follow-up. Fresh osteochondral allografting also appears to be effective in treating larger osteochondral lesions, where there are few other attractive alternatives. Fresh osteochondral allografts can thus be used to treat a wide spectrum of articular pathology. Technical refinements, and improvement in our understanding of graft-host interaction, as well as chondrocyte biology, should continue to improve clinical results. Disadvantages of fresh osteochondral allografting include the relative paucity of donor tissue, complexities in procurement and handling, and the possibility of disease transmission through the transplantation of fresh tissue. At present, only institutions that have overcome these obstacles seem capable of routinely performing this type of articular cartilage transplantation. In the future, as tissue banking and cartilage storage technology advance, fresh allograft tissue may become more available, allowing more widespread use of fresh osteochondral allografting in the treatment of articular cartilage lesions.     

自体镶嵌式骨软骨移植修复膝关节软骨缺损

目的 探讨膝关节软骨缺损的修复方法。方法 6例膝关节软骨缺损患者，关节镜下在其非负重区的软骨面上，用专用器械凿取圆柱状的骨软骨，并移植至软骨缺损部位，用于修复缺损。结果 随访2～24个月，患者的临床症状消失，关节活动度正常，MRI显示原软骨缺损区软骨表面平整，移植的骨软骨柱位置良好。结论 自体镶嵌式骨软骨移植术创伤小、操作简单、能保持关节面的曲度，是较为实用的手术。     

Silicone rubber: an alternative for repair of articular cartilage defects

Silicone-rubber implants were used to fill full-thickness articular cartilage in the trochlea area of the knee joint in rabbits, for the purpose of studying the long-term influence of silicone-rubber implant on surrounding articular cartilage. Forty eight weeks after surgery, the silicone rubbers were still fitted tightly into the defects; surrounding cartilage showed mild degeneration, better than the control group. Our results showed silicone-rubber implantation for repairing local articular cartilage defects can effectively delay the pathogenetic progression of osteoarthritis.     

Autologous chondrocyte transplantation

Since its introduction in 1987, autologous chondrocyte transplantation (ACT) for the management of full-thickness chondral defects of the knee has gained considerable attention and has renewed interest in cartilage repair. At this time there are patients with 10 to 13 years of follow-up who have continued to benefit from ACT. ACT is indicated for the management of full-thickness femoral articular Outerbridge grade III and IV lesions. Treatment of other surfaces such as the patella and tibia have also been successful. A thorough knowledge of patient selection and indications, good laboratory practices (GLP), standards of cell culturing, meticulous surgical technique, understanding of the normal time course of healing, the appropriate functional postoperative rehabilitation, and the management of specific ACT-related complications are all essential to good clinical outcomes. The success of this procedure with its excellent clinical outcomes and durability of the articular repair have made it a cost-effective procedure comparable to other technologies.     

MR imaging of autologous chondrocyte implantation of the knee

Autologous chondrocyte implantation (ACI) is a surgical technique that is increasingly being used in the treatment of full-thickness defects of articular cartilage in the knee. It involves the arthroscopic harvesting and in vitro culture of chondrocytes that are subsequently implanted into a previously identified chondral defect. The aim is to produce a repair tissue that closely resembles hyaline articular cartilage that gradually becomes incorporated, restoring joint congruity. Over the long term, it is hoped that this will prevent the progression of full-thickness articular cartilage defects to osteoarthritis. This article reviews the indications and operative procedure performed in ACI. Magnetic resonance imaging (MRI) sequences that provide optimal visualization of articular cartilage in the post-operative period are discussed. Normal appearances of ACI on MRI are presented along with common complications that are encountered with this technique.     

Comparison of fresh osteochondral autografts and allografts: a canine model

BACKGROUND: Osteochondral autografts and allografts have been widely used in the treatment of isolated grade IV articular cartilage lesions of the knee. However, the authors are not aware of any study that has prospectively compared fresh osteochondral autografts to fresh allografts with regard to imaging, biomechanical testing, and histology. HYPOTHESIS: The imaging, biomechanical properties, and histologic appearance of fresh osteochondral autograft and fresh allograft are similar with respect to bony incorporation into host bone, articular cartilage composition, and biomechanical properties. STUDY DESIGN: Controlled laboratory study. METHODS: Eighteen adult dogs underwent bilateral knee osteochondral graft implantation after creation of an Outerbridge grade IV cartilage defect. One knee received an autograft, and the contralateral knee received a fresh allograft. Nine dogs were sacrificed at 3 months, and 9 dogs were sacrificed at 6 months. Graft analysis included gross examination, radiographs, magnetic resonance imaging, biomechanical testing, and histology. RESULTS: Magnetic resonance imaging demonstrated excellent bony incorporation of both autografts and allografts. Biomechanical testing demonstrated no significant difference between autografts versus allografts versus control at 3 or 6 months (P = .36-.91). A post hoc calculation showed 80% power to detect a 30% difference between allograft and control. Histologic examination showed normal cartilage structure for both autografts and allografts. CONCLUSION: Fresh osteochondral autograft and fresh allograft tissues are not statistically different with respect to bony incorporation, articular cartilage composition, or biomechanical properties up to 6 months after implantation. CLINICAL RELEVANCE: The use of fresh allograft tissue to treat osteochondral defects eliminates morbidity associated with harvesting autograft tissue without compromising the results of the surgical procedure.     

Biomechanical and histological evaluation of osteochondral transplantation in a rabbit model

BACKGROUND: Biomechanical and histological properties of osteochondral transplantation have not been extensively examined. HYPOTHESIS: Osteochondral grafts have properties similar to native articular cartilage. STUDY DESIGN: Controlled laboratory study. METHODS: A 2.7 mm (diameter) x 4.0 mm (depth) osteochondral defect was created in 17 New Zealand white rabbit knees. An osteochondral graft, harvested from the contralateral knee, was transplanted into the defect. Eight rabbits were sacrificed each at 6 and 8 weeks. RESULTS: The 12-week grafts (1213.6 +/- 309.0 N/mm) had significantly higher stiffness than the 6-week grafts (483.1 +/- 229.1 N/mm; P <.001) and of normal cartilage (774.8 +/- 117.1 N/mm; P <.003). Stiffness of the 6-week grafts was significantly lower than normal cartilage (P <.036). At all time points, full-thickness defects had significantly lower stiffness than normal cartilage (P <.001). Histologically, transplanted grafts scored significantly higher than the full-thickness defects (P <.001). The defects showed inconsistent, fibrocartilage healing. The grafts demonstrated cartilage viability, yet with a persistent cleft between the graft and host. CONCLUSIONS: Osteochondral transplants undergo increased stiffness in the short term, with evidence of structurally intact grafts. Clinical Relevance: Osteochondral transplantation may be a viable treatment option; however, long-term investigation on graft function is necessary.     

Prospective evaluation of prolonged fresh osteochondral allograft transplantation of the femoral condyle: minimum 2-year follow-up

BACKGROUND: Focal articular cartilage lesions of the knee in young patients present a therapeutic challenge. Little information is available pertaining to the results after implantation of prolonged fresh grafts. HYPOTHESIS: Prolonged fresh osteochondral allografts present a viable option for treating large full-thickness articular cartilage lesions. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: This study presents the results of 25 consecutive patients who underwent prolonged fresh osteochondral allograft transplantation for defects in the femoral condyle. The average patient age was 35 years (range, 17-49 years). The average length of follow-up was 35 months (range, 24-67 months). Prospective data were collected using several subjective scoring systems, as well as objective and radiographic assessments. RESULTS: Statistically significant improvements (P < .05) were seen for the Lysholm (39 to 67), International Knee Documentation Committee scores (29 to 58), all 5 components of the Knee injury and Osteoarthritis Outcome Score (Pain, 43 to 73; Other Disease-Specific Symptoms, 46 to 64; Activities of Daily Living Function, 56 to 83; Sport and Recreation Function, 18 to 46; Knee-Related Quality of Life, 22 to 50), and the Short Form-12 physical component score (36 to 40). Overall, patients reported 84% (range, 25% to 100%) satisfaction with their results and believed that the knee functioned at 79% (range, 35% to 100%) of their unaffected knee. Radiographically, 22 of the grafts (88%) were incorporated into host bone. CONCLUSION: Fresh osteochondral allograft transplantation is an acceptable intermediate procedure for treatment of localized osteochondral defects of the femur. At 2-year follow-up, it is well incorporated and offered consistent improvements in pain and function. CLINICAL RELEVANCE: Prolonged fresh allograft transplantation is a safe and effective technique for addressing symptomatic osteoarticular lesions in the knees of young patients.     

A review of the evaluation and management of cartilage defects in the knee

In the orthopedic community, there is controversy regarding the management of articular cartilage defects of the knee. Nonoperative treatment is indicated for initial management. Surgical options include autologous chondrocyte implantation, osteochodral autograft transfer, osteoarticular allografts, and microfracture. More than 70% of patients who have surgery using these techniques have reported overall good results, and the literature does not clearly support the use of one technique over another. Treatment recommendations for each technique are based on differences in outcomes with respect to the size of the defect and the relative advantages and disadvantages of each. This article describes an approach to the evaluation and management of cartilage defects of the knee.     

Functional outcome of knee articular cartilage repair in adolescent athletes

BACKGROUND: Limited information exists about the treatment of full-thickness articular cartilage lesions of the knee in adolescent athletes. PURPOSE: To evaluate the functional outcome and athletic activity after articular cartilage repair in the knees of adolescent athletes. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty adolescent athletes with full-thickness articular cartilage lesions of the knee were treated with autologous chondrocyte transplantation. Functional outcome was evaluated by subjective patient outcome rating, knee activity scores, and level of athletic participation. RESULTS: At a mean of 47 months after autologous chondrocyte transplantation, 96% of adolescents reported good or excellent results with significant increases in postoperative Tegner activity scores and Lysholm scores. Ninety-six percent returned to high-impact sports and 60% to an athletic level equal or higher than that before knee injury. Return to preinjury sports correlated with shorter preoperative symptoms and a lower number of prior operations. All adolescents with preoperative symptoms < or =12 months returned to preinjury-level athletics, compared to 33% with preoperative intervals longer than 12 months. CONCLUSION: Treatment of full-thickness articular injuries of the knee in adolescent athletes with autologous chondrocyte transplantation yields a high rate of functional success at a mean follow-up of 47 months. The rate of return to demanding athletic activities is higher in cases in which the preoperative duration of symptoms is 12 months or less.     

Anterior cruciate reconstruction combined with autologous osteochondral transplantation

The purpose of this prospective study was to evaluate the results of simultaneous anterior cruciate ligament (ACL) reconstruction and osteochondral autograft transplantation performed in patients suffering an anterior instability associated with symptomatic full-thickness cartilage defects. Our clinical report includes the first 21 patients (six women, 15 men) who have been followed up for 32 months or longer. The average patient age was 29 years (range 22–44 years), and mean time from injury to the combined reconstructive surgery was 10 months (range 4–27 months). The cartilage defects had a mean area of 3.5 cm² (range 2.0–5.0 cm²). All patients were evaluated according to the IKDC, Lysholm and Tegner scoring scales by an independent observer. A visual analogue scale (VAS) reflecting patient pain was evaluated. Assessment using the IKDC knee scoring scale revealed 81% of the patients with a normal or nearly normal knee joint. There was a significant improvement in subjective discomfort, and the KT-1000 arthrometric evaluation showed a reduction of the ventral tibial translation (5.9 to 1.9 mm). All but two patients had returned to full activities without restriction and were asymptomatic. The results of this study suggest that symptomatic full-thickness articular cartilage defects associated with ACL instability can be effectively treated by performing ACL reconstruction and osteochondral autologous grafts in one procedure. However, only the years which follow will show the long-term outcome of the patients.     

Fresh osteochondral allografting

The treatment of articular cartilage defects in the knee is a difficult challenge. Fresh, small-fragment osteochondralallografting is a technique involving the transplantation of articular (hyaline) cartilage into the defective joint surface. The graft, a composite of living cartilage and a thin layer of underlying subchondral bone, provides a mature matrix with viable chondrocytes along with an osseous component that provides a surface for fixation and integration with the host. Fresh allografting is particularly useful in larger lesions (greater than 2 cms) or when associated osseous defects are present. Clinical experience with fresh osteochondral allografts now extends over 2 decades. Up to 90% of individuals treated for femoral condyle lesions are improved. The allograft tissue appears well tolerated by the host, with documented long-termsurvival of chondrocytes and intact matrix. Successful clinical outcomes have established fresh osteochondrall allografting as an appropriate alternative in the treatment of chondral and osteochondral lesions of the knee.     

Treatment of deep cartilage defects of the patella with periosteal transplantation

Twenty-six consecutive patients (19 men and 7 women) with a mean age of 31.5 years (range 19–52 years) who suffered from an isolated full-thickness cartilage defect of the patella (area ranged from 0.75 to 20.0 cm²) and disabling knee pain were treated with autologous periosteal transplantation (without any chondrocytes). The duration of symptoms was 59 months (range 11–144 months). During the first 5 postoperative days all patients were treated with continuous passive motion (CPM). This was followed by active motion, slowly progressive strength training, and slowly progressive weight-bearing. After a mean follow-up of 42 months (range 24–76 months), 17 patients (65%) were graded as excellent (were painfree), 8 patients (31%) as good (had pain with strenous knee-loading activities), and 1 patient as poor (had pain at rest). Twenty-two patients (85%) had returned to their previous occupation. Twelve patients (46%) had resumed sports or recreational activities at their former level. Repeated magnetic resonance imaging (MRI) investigations showed progressive, and finally complete, filling of the articular defects. Biopsies taken in five randomly selected cases showed hyaline-like cartilage. Patients with full-thickness cartilage defects of the patella and disabling knee pain can be treated with autologous periosteal transplantation (without any chondrocytes), followed by CPM, and slowly progressive strength training and weight-bearing. We believe this is a good method to accomplish regeneration of articular cartilage and satisfactory clinical results. Received: 25 March 1998 Accepted: 14 April 1998     

Magnetic resonance imaging of the femoral trochlea: evaluation of anatomical landmarks and grading articular cartilage in cadaveric knees

Purpose The purpose of the study was to define magnetic resonance imaging (MRI) findings before and after contrast medium opacification of the knee joint in cadaveric specimens to demonstrate anatomical landmarks of the trochlear surface in relation to the neighboring structures, and to evaluate different MRI sequences in the detection of cartilage defects of the trochlear and patellar surface of the knee. Materials and Methods The morphology and relationship of the proximal trochlear surface to the prefemoral fat of the distal femur were investigated by use of different MR sequences before and after intra-articular gadolinium administration into the knee joint in ten cadaveric knees. Anatomic sections were subsequently obtained. In addition, evaluation of the articular surface of the trochlea was performed by two independent observers. The cartilage surfaces were graded using a 2-point system, and results were compared with macroscopic findings. Results Of 40 cartilage surfaces evaluated, histopathologic findings showed 9 normal surfaces, 20 containing partial-thickness defects, and 11 containing full-thickness defects. Compared with macroscopic data, sensitivity of MR sequences for the two reviewers was between 17 and 90%; specificity, 75 and 100%; positive predictive value, 75 and 100%; negative predictive value, 20 and 100%, depending on patellar or trochlea lesions. Interobserver variability for the presence of disease, which was measured using the kappa statistic, was dependent on the MR sequence used between 0.243 and 0.851. Conclusion Magnetic resonance imaging sequences can be used to evaluate the cartilage of the trochlear surface with less accuracy when compared with the results of grading the articular cartilage of the patella.     

Autologous chondrocyte implantation in the knee using fibrin

Autologous chondrocyte implantation (ACI) is widely used to treat symptomatic articular cartilage injury of the knee. Fibrin ACI is a new tissue-engineering technique for the treatment of full-thickness articular cartilage defects, in which autologous chondrocytes are inserted into a three-dimensional scaffold provided by fibrin gel. The objective of this study is to document and compare mean changes in overall clinical scores at both baseline and follow-up. Fibrin ACI was used to treat deep cartilage defects of the femoral condyle in 30 patients. There were 24 men and 6 women with a median age of 35 years (range 15–55) and with a mean defect size of 5.8 cm² (range 2.3–12). Clinical and functional knee evaluations were performed using different scoring systems, MRI was performed 24 months postoperatively, and arthroscopy was performed 12 months postoperatively. All patients achieved clinical and functional status improvements following surgery (P < 0.01). The mean scores of the Henderson classification (MRI evaluation) significantly improved from 14.4 to 7 (P = 0.001), and no graft-associated complications were noted. Arthroscopic assessments performed 12 months postoperatively produced nearly normal (grade II) International Cartilage Repair Society scores in 8 of the 10 study patients. Fibrin ACI offers the advantages of technical simplicity, minimal invasiveness, a short surgery time, and easier access to difficult sites than classical ACI. Based on the findings of this clinical pilot study, we conclude that fibrin ACI offers a reliable means of treating articular cartilage defects of the knee.     

Grading articular cartilage of the knee using fast spin-echo proton density-weighted MR imaging without fat suppression

OBJECTIVE. The objective of this work was to determine the accuracy of fast spin-echo proton density-weighted MR imaging in the evaluation of the articular cartilage of the knee using arthroscopy as a gold standard. MATERIALS AND METHODS: We retrospectively reviewed MR images of the knee in 54 patients for whom arthroscopic results were available. All MR imaging studies included fast spin-echo proton density-weighted coronal and axial sequences as part of our routine protocol. Evaluation of the articular surfaces was performed by three independent observers who were unaware of the arthroscopic results. The cartilage surfaces were graded using a 3-point system, and results were compared with arthroscopic findings. RESULTS. Of 324 cartilage surfaces evaluated, arthroscopy showed 241 surfaces as normal, 56 as containing partial-thickness defects, and 27 as containing full-thickness defects. Compared with arthroscopic data, sensitivity of MR imaging for the three reviewers was 59-73.5%; specificity, 86.7-90.5%; positive predictive value, 60.5-72.6%; negative predictive value, 86.0-90.8%; and accuracy, 79.6-86.1%. Interobserver variability for the presence of disease, which was measured using the kappa statistic, was 0.63. CONCLUSION. Fast spin-echo proton density-weighted MR imaging sequences can be used to evaluate the cartilage of the knee with accuracy comparable to that of previously reported cartilage-specific sequences.     

Articular cartilage lesions in 993 consecutive knee arthroscopies

BACKGROUND: Traumatic articular cartilage injuries heal poorly and may lead to development of osteoarthritis at a young age. This study estimates the number of patients who may benefit from one of the surgical methods of cartilage repair. METHODS: All patients undergoing knee arthroscopy during a 6-month period at three collaborating hospitals were consecutively evaluated according to the International Cartilage Repair Society (ICRS) knee form. The material consists of 993 consecutive knee arthroscopies in patients with median age of 35 years. RESULTS: Preoperative radiographs demonstrated degenerative changes in 13% of the knees. Articular cartilage pathology was found in 66% and a localized cartilage defect was found in 20% of the knees. A localized full-thickness cartilage lesion (ICRS grade 3 and 4) was observed in 11% of the knees. Of the localized full-thickness lesions, 55% (6% of all knees) had a size above 2 cm(2). CONCLUSION: Eleven percent of all knee arthroscopies show cartilage defects that may be suitable for cartilage repair procedures. However, the natural history of these lesions and the number of patients that will benefit from a cartilage repair procedure are so far unknown.     

Three-year clinical outcome after chondrocyte transplantation using a hyaluronan matrix for cartilage repair

Repair of articular cartilage represents a significant clinical problem and although various new techniques - including the use of autologous chondrocytes - have been developed within the last century the clinical efficacy of these procedures is still discussed controversially. Although autologous chondrocyte transplantation (ACT) has been widely used with success, it has several inherent limitations, including its invasive nature and problems related to the use of the periosteal flap. To overcome these problems autologous chondrocytes transplantation combined with the use of biodegradable scaffolds has received wide attention. Among these, a hyaluronan-based scaffold has been found useful for inducing hyaline cartilage regeneration. In the present study, we have investigated the mid-term efficacy and safety of Hyalograft C grafts in a group of 36 patients undergoing surgery for chronic cartilage lesions of the knee. Clinical Outcome was assessed prospectively before and at 12, 24, and 36 months after surgery. No major adverse events have been reported during the 3-year follow-up. Significant improvements of the evaluated scores were observed (P < 0.02) at 1 year and a continued increase of clinical performance was evident at 2 and 3 years follow-up. Patients under 30 years of age with single lesions showed statistically significant improvements at all follow-up visits compared to those over 30 with multiple defects (P < 0.01). Hyalograft C compares favorably with classic ACT and is particularly indicated in younger patients with single lesions. The graft can be implanted through a miniarthrotomy and needs no additional fixation with sutures except optional fibrin gluing at the defect borders. These results suggest that Hyalograft C is a valid alternative to ACT.